fix(data): address code review findings

- Fix sort order regression in GetByListIdAsync (was descending, should be ascending)
- Restore WAL mode pragma (was silently dropped in EF migration)
- Add existing-DB compatibility shim in MigrateAndConfigure (baselines InitialCreate
  migration for databases created by the old schema.sql)
- Remove dead AddDbContext/AddScoped registrations from Worker (only IDbContextFactory
  is used by singleton consumers)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/ClaudeDo.Installer/Steps/InitDatabaseStep.cs

@@ -19,7 +19,7 @@ public sealed class InitDatabaseStep : IInstallStep
                 .UseSqlite($"Data Source={expandedPath}")
                 .Options;
             using var context = new ClaudeDoDbContext(options);
-            context.Database.Migrate();
+            ClaudeDoDbContext.MigrateAndConfigure(context);
 
             progress.Report("Schema applied successfully");
             return Task.FromResult(StepResult.Ok());